Bubbly, easy-going and blessed with an infectious laugh, Alice Leadbeter is great company. Her house has the cosily chaotic feel of a large, happy family – photos of sons James, 10, Thomas, 8 and Harry, 5, smile down from every wall, and toys fight for space with colourful beads and yarns; as well as being a primary school teacher, Alice is a keen knitter and jewellery-maker.

But the craft projects are taking a back seat at the moment, as the 40-year-old is in training to run the London Marathon next Sunday. And her chosen charity? Mind. Because in spite of her cheerful nature, not so long ago Alice was in the dark depths of postnatal depression: “At my worst, I didn’t think I’d ever recover,” she says. “But now I’m better than I’ve ever been.”

Alice, who lives in Burwell, always wanted to be a mum. She and husband Ian were delighted when James was born and, with no history of depression, revelled in her time with her new baby.

“I’m a perfectionist, as many teachers are; we have very high standards, and I remember thinking ‘Gosh, my life’s so much easier now, I’ve got so much more time than when I’m teaching’!” says Alice, laughing. “I had time to actually think about what I was going to wear in the morning, and maybe put a bit of make-up on…”

But when Thomas arrived, Alice wasn’t quite so breezy: “I was on the edge, I think. I had a lovely health visitor who was watching me: she just picked up that I was not ‘not coping’, but just mentally not quite where I should be. But then when I had Harry it all fell apart.”

During her pregnancy, life had become increasingly stressful for Alice. Little Thomas was very poorly with asthma, “and we spent a lot of time in the hospital with him, which was obviously really worrying,” she recalls.

“Every mum wants everything to be perfect for their children. You want them to have a wonderful upbringing and a great childhood, so I nearly killed myself trying to be here for James, as well as for Thomas in hospital, and trying to make it all alright.”

When Harry arrived, Alice struggled from the beginning. “There were lots of tears. Lots and lots of tears,” she says. “I loved my children to bits, and I would do anything for them, but I remember lying on the bed upstairs in absolute tears, thinking ‘I can’t do this’.

Gradually, she felt herself withdrawing: “You almost shut down from the outside world. You’re in this little bubble, and nobody knows. I put on this big act; even people who were fairly close to me didn’t know because I kept them at a distance.”

But at home Alice couldn’t hide and, she says, it was particularly tough for Ian: “When I was crying, he’d just say ‘What’s wrong?’ And I’d be like ‘I don’t know!’

“It’s so hard for the person watching you going through something, because they desperately want to help, but don’t really know how. I can’t fault him; he was brilliant and very hands-on. But I just shrank away from everybody.

“It wasn’t as extreme as some,” she adds. “Some people want to kill their children. But I could see that! I loved this thing with all my heart, but the demands it was expecting,” she says, shaking her head. “It’s mentally and physically draining, because they want you all the time.”

Alice’s other issue was that she was never able to relax: “I couldn’t stop. I’d either be crumpled in tears or I’d be manic. The house had to be perfect – you can tell my standards have dropped! – but I had to have a perfect house, everything had to be ironed... I remember people saying to me ‘It doesn’t matter,’ and I’d be like ‘but it DOES!’ I had such high expectations.”

Luckily for Alice, her health visitor recognised that something was seriously wrong, even though at first she refused to admit it: “Who’s going to say ‘Do you know what, I’m really not coping’?” she says. “You’re not! You’re a mother, you’re expected to cope. How often have you got those images of the perfect family thrown at you in the media? You can’t fail, and yet you do feel like a failure.

“I used to think ‘What’s wrong with me? I’ve got three beautiful children, I’ve got everything I should want, but I’m not happy’. It’s horrid, really horrid, because you’re embarrassed. How can you admit to somebody that actually it’s not going right?”

But Alice’s biggest fear was what might happen to her children if she told the truth: “It must have been in the back of my mind that they might be taken away because I couldn’t cope. I thought ‘If I can’t look after them, what’s going to happen?’

“It is really hard, but in order to get better, you have to admit that there’s a problem. And once I did reach out, I found that I had an amazing team behind me.”

The health visitor had clearly voiced her worries to Alice’s GP and, when she went for her six week check-up, the doctor was ready: “She was just who I needed; she’s a mother, and she made it sound normal.” The doctor gave Alice some leaflets; by chance there was a postnatal depression group in the village, “and I phoned this lady, who came round to visit me.

“She was brilliant, because she’d been through it herself, but I remember sitting here thinking ‘I’ll never be able to be like her. I can’t ever imagine recovering, and being like she is. There’s no way out of this’.

“But she was the one who introduced me to knitting again. She said ‘I used to knit things for my daughter’s dolls, and I felt like I was doing something for her, but actually it was a way of sitting down’. And that was brilliant. I knitted as a teenager, so I just started again; it just meant that I could sit still and not feel guilty. Knitting is amazing because all you’re worrying about is the next stitch: you’re focused that, rather than on everything else that’s going on.”

Alice’s next step was to have counselling: “I’d got to a point where I realised I couldn’t go on like this, and I needed to throw everything I could at it. So I did. Counselling’s not right for everybody, but I was desperate. My counsellor was wonderful, and said ‘Focus on you: if you can’t look after yourself, then you can’t look after everybody else’.”

Moreover Alice realised, with sadness, that she needed to give up her job. “It was a very hard decision. I was worried about what people would think of me - the general perception of mental health is that you’re completely nutty - and I was thinking ‘Will I ever get another job if it goes on my file?’

“But I wanted to get better, even though I didn’t actually believe I could at the beginning. So I just thought ‘I’m going to stop, spend the time with my children, and take one stress out of my life’.” She also decided to take anti-depressants, something she’d avoided to begin with: “Again, it’s another step to actually saying ‘You know what? I’ve accepted it’. And it’s just like any other medication: if it’s going to help you, what’s wrong with it? I just wanted to feel better.”

For Alice, it worked. She busied herself with being the best mum she could be and, ever-energetic, threw herself into learning to make jewellery – and writing a blog about it. “When I wasn’t working, it was almost like I wasn’t a member of society, and that’s when blogging really helped - it was a connection with other people. I love it.”

Today, Alice feels better than ever, not least because she’s back at work. With Harry starting school last September, she decided that the time was right, and now does a job-share at a local primary: “I really do love teaching,” she says. “Once a teacher, always a teacher...”

So what would her advice be to someone who suspects they may have postnatal depression? “Don’t struggle on your own. If you can find a doctor who you really like, and who you think will listen to you, go and see them - even if it means waiting for a week. And don’t be afraid! I know it’s really hard, but people will understand. I’ve never felt anybody judging me in a negative way because of what I’ve admitted to.

“Sometimes it takes an awful lot of courage to say ‘I gave up work because…’ or ‘I suffered from postnatal depression’, but most of the time people say ‘Ooh, I know somebody else who did’, or ‘Do you know what? I suffered from that too’.”

For the moment, Alice is focusing on next weekend’s Marathon, which she’ll be running for Mind – a charity she chose because of its determination to get people talking about mental health problems: “We need to get rid of the stigma. One in four people will be affected, which is an amazing statistic, and we really shouldn’t look at anybody differently. It’s an illness like any other illness, and if I can help one person by being open about it, it’ll be worth it.

“I’ve learned a lot about myself,” she adds. “I’ve learned it’s normal to have dips - in fact I cried yesterday morning - but now I can recognise when I’m feeling a bit low, and I’ve got strategies to deal with it. I’ll say ‘OK, I need to go out for a run now’.

“Running is my headspace. Even when the children are upstairs asleep, you’ve still got one ear open, but when you go for a run you’re completely on your own. My mind just free-wheels. It’s just my time.

“And actually just getting outside in the fresh air and seeing the countryside, especially at this time of year, is amazing,” she adds with a smile. “I might be feeling rubbish, but look, spring is on its way! You start seeing the flowers and the buds, and it’s just great. Life is lovely.”

::Postnatal depression is thought to be caused by the hormonal changes that occur after pregnancy combined with the physical and emotional stress of looking after a newborn. It affects as many as one in seven women and, according to the NHS, is unlikely to get better by itself quickly; do contact your GP if you think you or your partner is affected.